Problems associated with myocardial ischemia due to coronary artherosclerosis continue to represent the greatest cause of death in the United States and the countries of Western Europe. When the heart receives inadequate blood flow, altered ventricular performance follows and can be documented by objective means. Our interest has been primarily in the development of noninvasive radionuclide angiocardiography as a simple, safe, relative inexpensive, and noninvasive technique which permits quantitative evaluation of cardiac function in patients with coronary artery disease. These studies will continue and a major objective will be the creation of acute and chronic primate models of ischemic heart disease with studies of altered myocardial blood flow, oxygenation, work, and metabolism. Animal preparations with chronic implantation of sonar crystals will be employed to assess regional myocardial function and metabolism. Moreover, these techniques are now applicable to the clinical situation and their use will be employed to indicate specific therapeutic roles intraoperatively and following coronary revascularization procedures.